Lifting jack



July 30, l 929.

H. W.. CLARK I LIFTING JACK Filed Dec. 16, 1927 2 Sheets-Sheet Jnventm, HW 67m? 72.

Filed Dec. 16, 1927 2 Sheets-Sheet 2 /////////.////////////Ill/Ml/ Unueufm.

Patented July 30, 1929.

siren eras titansrarer HAROLD CLARK, F ALLIANCE, CHIC, ASSIGNGB TO THE BUCKEYE JACK COMPANY,

OF ALLIANCE, OHIO.

LIFTING JACK.

Application filed December 16, 1927. Serial No. 240,365. 7

tomotive passenger cars, trucks, basses, etc,

it has been found necessary to use a jack hav ing the maximum lift in relation to the height of the closed Jack. It is further desirable to provide a jack where the top screw is large in diameter and securely guided by the frame so as to be strong against side strains and loads which are encountered and to provide so that no vertical load is carried on the rotating gear or gear box or by means for connecting screws and preventing them from revolving. v

lVith these and other objects in view, the invention consists in certain novel features of construction and combination of parts which are hereinafter described and as shown on the following drawings:

Figure 1 isa vertical central section of one form of my jack extended. I

:Fig. 2 is a vertical central'section of same *showing the jack extended.

Fig.3 is a horizontal section of my jack taken on line AA of Fig. 1.

Fig. 4 is a side View of the lower end of .the sleeve.

In the particular embodiment shown in the drawings, 1 is a base on which is carried the vertical hollow frame 5 supporting at its up- :3 per portion hollowgear box 6 which I prefer to form integrally with the frame. This gear box 6 is open at its sides so that the main rotating gear 7 can be entered through said opening. Driving pinion 8 is provided with teeth meshing with teeth of gear 7. Pinion 8 is rotatedby means of a suitable handle or rod 9 which I have indicated butnot shown in full.

I Attached to base 4: I provide an upstandand if difterentthe screw with the greater pitch will have a greatertravel for a given rotation of the driving nut 12.

Screw 16 supports at its upper end load plate or saddle 17 which is attached to screw by pin 18 which permits saddle 17 to oscillate slightly to conform to the character of the loadcarried thereby,

Traveling nut 12 is provided with slots 19 and 20 on its outer surface which engage lugs on driving gear 7 and provide means whereby the nut 12 is rotated by gear 7 and still be free to slide up and down as it is elevated or depressed by the action ofthe threads 13 revolving on threads 11 of the stationary screw 10.

Screw 16 is held from rotating by means of telescoping sleeve 21 which is carried in nut 12 and is provided at its upper end with lugs 22 and 23 which engage keyways 2-l25 cut on the inside surface of upper screw 16. Now

sleeve 21 is kept from rotating by the novel construction of the internal screw 10 which I make of a non-circular form. I show this screwto be hexagonal in section on my drawings as in Fig. 3, but it may be ofany other non-circular form which will allow the sleeve 21, which is of similarform, to telescope over screw 10 and be kept from rotating thereby. I prefer to make the lower end of sleeve 21 of hexagonalshape so as to conform to the shape of screw 10. At upper end of screw lO, I provide a shoulder as at 26 to prevent disengagement of sleeve 21 from screw 10 when the jack is fully extended,or in case the jack is turned up side down. It will thus be seen that since screw 10 is held rigidly to stationary base l, it will not revolve, and will in turn by its non-circular form keep sleeve 21 from rotating, and that sleeve 21, by its lugs 22 and 23 which slide in keyways in traveling screw 16, will prevent screw 16 from revolving. The rotation of nut 12, which is set up by gear 7, therefore will cause the nut to rise or fall, as the case may be, upon screw 10, and a corresponding rise or fall will be caused by upper hollow screw 16 moving in the upper threads of nut 12. When the jack is elevated as in Fig. 2, it will be seen that the smaller screw 10 is completely enclosed and .any side strains will come upon the large up per screw 16 which is firmly held by large nut 12, and the nut in turn held in frame 5.

Where the jack is depressed as in Fig. 1,

the sleeve 21 telescopes down over screw 10 and upper large screw 16, which is hollowed out, telescopes over sleeve 21 and rests 1ns1de of traveling nut 12. The internal threads 13 use of bevel gear and pinion for rotating the traveling nut, but I may make. use of other forms of gears such as spur gears, worm and worm gears, etc. for this purpose. 7

It will be observed from Fig. 1 that my jack is extremely compact when depressed and thatv when fully extended it closely approaches the maximum theoretical height. 7

Having fully explained my invention, what I claim as new and desire to secure by Letters- Patent is 1. A jack consisting of a main frame, a lower screw secured thereto, an upper screw adapted to telescope over said lower screw when jack is depressed, atraveling nut member having threads to engage the threads of said screws, a sleeve carried in said nut, being held'from turning by the lower screw and having means for preventing the upper screw from turning.

2. A jack consisting of a main frame, a lower screw secured thereto, an upper screw adapted to telescope over said lower screw when jack is depressed, a traveling nut memher with internal threads engaging external threads on said screws, a non-rotating sleeve carried in said nut and a gear to rotate the.

nut.

3. A jack'consisting of a main frame, a lower screw secured thereto and kept from turning thereby, a nut traveling on said screw, an upper screw with threads engaging the threads of the nut, a non-rotating sleeve carried by the nut, held from rotating by the lower screw and in turn keeping the upper screw from rotating, means for rotating said nut'held from vertical movement by the frame.

i. A jack consisting of a stationary main frame, a lower screw secured thereto, said screw being of non-circular form, a nut traveling on said screw, an upper screw with threads engaging the threads'of the nut, a sleeve carried by the nut, the lower end of said sleeve being formed to telescope over the lower screw but kept from turning by the form of said screw, projections on upper portion of said sleeve adapted to engage slots in telescope over lower screw when jack is de.

pressed, a sleeve carried in said nut and held from turning by the lower screw and provided with means to hold the upper screw from turning and means for rotating the traveling nut, said rotating means being held 'from' vertical movement by the main frame.

I 6. A jack consisting of a stationary frame, an, upright screwsecured thereto, said screw being of a non circular form, a; nut traveling on said non-circular screw, an upper hollow screw, with threads engaging the threads of traveling nut, a sleeve carried by the nut, the sleeve arranged to telescope over stationary screw and kept from turning by the non-circular form of said screw, lugs on upper part of sleeve engaging internal keyways in hollow screw to prevent hollow screw from revolving, a driving gear having lugs engaging slots on outer portion of traveling nut and means for rotating said driving gear.

7. A lifting jack having a plurality of screws, one of which is of non-circular form and a sleeve telescoping over said non-circular screw but maintained in rotative relation thereto by'conforming to the shape of said screw. I V

8. A lifting jack having. a plurality of screws, one of which is of non-circular form,

a sleeve telescoping over said circular screw but maintained in rotative relation thereto by the form of said screw, a second screw telescoping over said sleeve and means for maintaining said outer screw in rotative relation to said sleeve. 1 i

9. A lifting ack having a plurality of vertical screws, the inner screw being of noncircular form, a sleeve telescoping over said screw and by its form, maintained in rotative relation thereto, an outer screw telescoping over said sleeve and maintained in rotative relation thereto, a nut with right and left hand internal threads to engage corresponding external threads on the said screws.

In testimony whereof, I have signed this specification.

HAROLD w. CLARK. 

